… Of course not, neither did I. Why would we when we have those exotic things listed above to distract? But the article I’m about to discuss comes from a group of physical therapy researchers in Brazil who decided to study a particular treatment option for a very common type of knee injury.

There are many names for it: Runner’s Knee, Osteoarthritis, Retro-patellar pain, Chondromalacia, Patellofemoral Syndrome or Patellofemoral Pain Syndrome (PFPS). For convenience we will refer to the injury as PFPS, since that is the terminology used by the article. It is essentially a form of arthritis that develops on the backside of your patella.

PFPS is most commonly associated with athletic females in sports that require a lot repetitive knee bending, such as, volleyball or long distance running. Now, I don’t know about the other male therapist out there, but working with the Brazilian Women’s National Volleyball team would be awesome! And, I’m sure female therapist would love to work with the men’s team too. I mean come on… these people kick butt in volleyball on a worldwide scale, and… they’re hot!

http://blog.casinobeach.com/images/brazil-beach-volleyball.jpg

But, alas, this article isn’t about athletes. While PFPS is common amongst athletes, there are still plenty of occurrences in the sedentary population. Fukuda et al. performed a randomized control trial on the effect of hip abduction and lateral rotation exercises on reducing pain and improving function in people with PFPS.

Hip Abduction

*For those unfamiliar with the terminology: Hip abduction would be keeping your leg straight and lifting it out to the side, away from your opposite leg. Hip lateral rotation would be keeping your leg straight and rotating it on your heel so your foot and knee both move outward.

They divided 70 females into three different groups. The control group had 25 subjects and received no treatment; they were just told to resume their normal daily activity. The Knee Exercise group (KE) had 22 subjects and they were given stretching and strengthening exercises that focused on the knee only. The third group, Knee and Hip Exercise group (KHE), had 23 subjects and they were given stretching and strengthening exercises for the knee and hip. See Table 1 and 2 below for a complete list of exercises.

Taken from Fukuda et al.

The study was performed over the course of 4 weeks, with measurements taken before exercises were given, and at the end of the 4-week treatment period. The measurements included: Lower Extremity Functional Scale (LEFS), Anterior Knee Pain Scale (AKPS), single-limb single hop test, and pain while ascending/descending stairs as recorded on an 11-point numerical pain rating scale (NPRS). The LEFS and the AKPS are questionnaires that subjects fill out to help quantify how their injury affects them throughout the day.

So, lets take a look back at the two exercise groups in Table 1 and 2. If you’ll notice, the KHE group has the same exercises as the KE group, plus a few more. These additional exercises are pretty basic to strengthening muscles that perform hip abduction and lateral rotation.

Now, you may be asking, “How does strengthening hip abduction and lateral rotation going to help my PFPS?” Well… try this first:
- Do a push-up. Either on your knees or on your toes (Girl vs. Guy push-ups).
- Now, get ready to do another push-up. Your fingers should be pointing forward.
- Turn your hands inward so your fingers are pointing towards your opposite shoulder.
- If you’re not too uncomfortable holding this position, try a push-up again.

Builds muscle.

Builds hospital bills.

I don’t know about you, but doing push-ups this way hurts my shoulder and elbow. I DO NOT recommend you try it this way in the future.

It’s all about body mechanics. When we squat down, our knees and toes should point forward, or maybe slightly outward (lateral rotation). Many researchers have found, biomechanically, that people with PFPS may be medially rotating their hip (turning their knee inward) as they squat down or ascend/descend stairs. It's similar to having you do that crazy push-up I described above. In the case of your knee, it places awkward stresses on your patella, which over time can cause early degeneration of the cartilage underneath your patella and early arthritis. By strengthening the muscles that perform hip abduction and lateral rotation, hopefully that tendency to medially rotate is reduced.

So what did they find between the three groups in this study?

Well… as expected, the KE and KHE groups both improved significantly at the end of the 4 weeks, while the control group did not. When looking at the changes in LEFS, AKPS, and single-limb single hop test, both KE and KHE groups were equally as affective. But, when looking at changes in NPRS, only the KHE group had significant decreases in pain while ascending/descending stairs.

In addition, the KHE group showed a minimum clinically important difference in all outcome measures, while the KE demonstrated this only in LEFS.

*Minimum Clinically Important Difference (MCID) is the smallest improvement that would be beneficial to a patient. Hypothetical example: imagine you take a medicine to make your nose 25% less congested when you are sick. This is considered a significant improvement in drug development. But come to find out, even at 25% less congested, you still can’t breathe well. That medicine did not provide an acceptable MCID.

The Takeaway Message:
Strengthening hip abductors and lateral rotators may help reduce/prevent PFPS. No definite conclusions can be drawn from one study, but it does show promise. One thing to keep in mind is they only strengthened muscles in this study; they did not address correcting the subject’s movement mechanics. It’s analogous to having someone strengthen muscles in their back, but not learning how to assume and maintain a good upright posture. In my opinion, strengthening is a supplement to teaching good mechanics and posture.

Thanks for reading. I’ll let you guys know when I make it down to Brazil and start working with their women’s volleyball team. My 2012 goal: Going to London with 6-foot tall beautiful women and taking the Gold!

Abstract:STUDY DESIGN: Randomized clinical trial. OBJECTIVE: To investigate the influence of strengthening the hip abductor and lateral rotator musculature on pain and function of females with patellofemoral pain syndrome (PFPS). BACKGROUND: Hip muscle weakness in women athletes has been the focus of many recent studies and is suggested as an important impairment to address in the conservative treatment of women with PFPS. However, it is still not well established if strengthening these muscles is associated with clinical improvement in pain and function in sedentary females with PFPS. METHODS: Seventy females (average ± SD age, 25 ± 07 years), with a diagnosis of unilateral PFPS, were distributed randomly into 3 groups: 22 females in the knee exercise group, who received a conventional treatment that emphasized stretching and strengthening of the knee musculature; 23 females in the knee and hip exercise group, who performed exercises to strengthen the hip abductors and external rotators in addition to the same exercises performed by those in the knee exercise group; and of the 25 females who did not receive any treatment. The females of the nontreatment group (control) were instructed to maintain their normal daily activities. An 11-point numerical pain rating scale (NPRS) was used to assess pain during stair ascent and descent. The lower extremity functional scale (LEFS) and the anterior knee pain scale (AKPS) were used to assess function. The single-limb single hop test was also used as a functional outcome to measure preintervention and 4-week postintervention function. RESULTS: The 3 groups were homogeneous prior to treatment in respect to demographic, pain, and functional scales data. Both the knee exercise and the knee and hip exercise groups showed significant improvement in the LEFS, the AKPS, and the NPRS, when compared to the control group (p<.05 and p<.001, respectively). But, when we considered minimal clinically important differences, only the knee and hip exercise group demonstrated mean improvements in AKPS and pain scores that were large enough to be clinically meaningful. For the single-limb single hop test, both groups receiving an intervention showed greater improvement than the control group, but there was no difference between the 2 interventions (p>.05). CONCLUSION: Rehabilitation programs focusing on knee strengthening exercises and knee strengthening exercises supplemented by hip strengthening exercises were both effective in improving function and reducing pain in sedentary women with PFPS. Improvements of pain and function were greater for the group that performed the hip strengthening exercises, but the difference was significant only for pain rating while descending stairs.